dashaint

I'm looking at doing something that will give me more performance to my 2000 silverado 2500 4x4. It's a heavy truck and is slow off the line. I already have CAI and pacesetter long tubes.

It's a LQ4 6.0 iron block.

From what i have found here's some things I could do:

high-flow catalytic converters
LSXRT intake with 102 mm Big Mouth TB
fuel injectors from an 8.1 L engine or 42 lb ones.
then a cam... but i'll switch to a LQ9 If going to do that

my questions:

can i bolt on everything and drive it without a custom tune?
Will i need a bigger fuel pump or do anything with the fuel lines with the LSXRT & Big Mouth?
what else would you recommend specifically? (limited budget of 2k)

dashaint

bobfig

imo gears and a 2800rpm stall with a tune.

redtan

iTrader: (5)

Cats are worthless since you already have the headers. If anything those might lose power. Get those if you want to tone down the exhaust and smell not for performance.

Intake manifold is a good idea, you won't need new injectors at these power levels.

Basically a cam along with the FAST intake will be your best bets, and a stall as previously mentioned. Those will need a retune of course.

poltergeist 02

iTrader: (65)

If you do try to throw all of the parts that you have on it without a tune, leave the injectors off until you get it to a tuner.

dashaint

good stuff, thanks yall.

NorCalAnthony

Did you or the PO do a regear when the lift and bigger tires were put on? A lot of people skip that step for whatever reason and lose a lot of the performance feeling having the bigger tires and little stock 3.42's... If so, I'd start there and then work your way up to doing a cam and matching stall. You may also want to look at swapping to an intake from a newer truck (08+). Lots of guys over at performancetrucks.net have made some nice gains with them and you can get one with the newer better flowing injectors pretty easily for a fraction of what the LSXRT intakes cost...

Rise of the Phoenix

iTrader: (27)

You'll want to get it tuned after doing all of that stuff. Kind of pointless to do it without getting a tune in my opinion. It's not safe, nor is it going to optimize your performance mods.

A.R. Shale Targa

iTrader: (2)

IMO making the engine more powerful will go somewhat unnoticed since the big heavy truck with large tires/wheels is under geared.
I'd put 4.10s and a 2800 stall with a retune and then look to more power, cam, heads, etc. when funds provide.

elephantrider

iTrader: (2)

regear and a stall will make it feel like a new truck, along with a solid
tune.

Darth_V8r

iTrader: (4)

another vote for gears and stall. On the motor side, the first thing I'd do is mill those heads to get some compression

crip

does the truck have a programmer or custom tune? everything i own i get tuned. it makes a difference without a doubt. but as everyone else has said gears/stall/tune. i would prob go in the order of tune, gears, and then stall though.

CattleAc

iTrader: (7)

He should have the "873" cast iron heads on his 2000, they are essentially the same as the later aluminum 317's...correct???

Darth_V8r

iTrader: (4)

I'm not sure, to be honest. Either way, I know the compression is lower than optimal, so if they get milled to a 65 cc chamber, he'll pick up some power and efficiency

dashaint

thx for the info, i have 3.73 ratio.. i tried 4.10 before, didnt like how high it revved on the highway. i like the idea of saving money on the intake ... i found this, will it work on my engine? http://www.ebay.com/itm/L92-Intake-Manifold-With-Fuel-injector-Rail-engine-Cover-/221772744632?hash=item33a2af87b8&vxp=mtr

also, these intakes have 4 bolt throttle bodies looks like. mine is fly by cable.. so i'd have to get another throttle body for this as well? which one? all the ones made for this would be fly by wire... being so new.

dashaint

I like the 3.73 gears on the highway, plus it's 4x4 so if i change i'd have to change both diffs... so i might have to live with it being 3.73.

I could do the torque converter, I have no idea what stall to get. i've heard from anywhere from 2200 to 2800. i have done some research on what they do, although i still don't understand what the rpm range has to do with anything. at one point i thought it was for racing, where you could hold the brake just under the stated rpm range and then it would lock up when you punched it and let off the brake. but i dont believe that was accurate whatsoever. so... i don't know what to think when it comes to selecting a torque converter. if it allows higher revs taking off.. then that'd be good i'm guessing. not sure.

93Z2871805

iTrader: (5)

As said above, stall, gears, tune.

Think of it as a pre-set clutch engagement with a torque multiplier. If the stall is say 2800, the coupling will essentially slip until 2800 before it allows torque to be transferred to the trans. Raising the stall lets the motor hit at a higher RPM (closer to peak torque) for launch and during a shift. The idea is to keep the motor in it's power band (point between peak torque and peak HP) on launch and while in each gear.

NorCalAnthony

Close but no, that one's for an L92 with the rectangle ports and you'd need one with the cathedral ports to match your existing heads. Any of the Trailblazer SS intakes or 4.8/5.3 intakes from '08 up are what you'll want to look for. Ebay was kind of hit and miss when I was looking for mine but you can usually find a good deal in the classifieds here and at performancetrucks.com (this forum's sister site). I think I paid $140 for mine complete with sensors, fuel rail, injectors, and TB... fyi if you want to go this route you'll also need a larger 90-92mm 4 bolt throttle body that that run anywhere from $100 for a cheap ebay one on up to $400ish for a high quality one from Holley or Nick Williams (which can also usually be found cheaper in the classifieds).

As far as the rest of the mods go, what are your goals and budget? As already mentioned, milling your heads is an easy way to pick up compression to help power and efficiency. If you do have the iron heads check the price with your local machine shop because it may be cheaper to pick up a set of lightly used 799/243 heads.

For the stall, your intended use for the truck will be a big factor. For a truck that sees any type of towing or is lifted like yours I'd keep it on the smaller side to help get it moving and keep the trans temp down.

Camshaft selection will also be based on intended use and budget. Brian Tooley and Cam Motion make some great "drop in " cams specifically for trucks that make nice power are designed to be used with the cheaper LS6 springs and stock stall. You can also talk to one of our sponsors life Martin at Tick about getting a camshaft custom spec'd for your setup for about the same price as an off-the-shelf cam. If you want to go with a more radical cam be prepared to spend more on matching components like better/more expensive springs, higher stall converter, etc.

dashaint

I'm trying to locate one, part no. 12580420 is best i can locate http://www.rockauto.com/catalog/raframecatalog.php?a=Search%2Bfor%2BACDELCO%2B1258 0420&catalog=351&partnum=12580420&ck[ID]=0&ck[idlist]=0&ck[viewcurrency]=USD&ck[PHP_SESSION_ID]=1bucepvnh3e5la9ndku1h4pk44, but not sure if is right. i'm ordering something on wednesday. so i need to find one. preferably complete with rails, injectors... and will have to get some kind of TB too

NorCalAnthony

Great explanation. Just wanted to add for the OP that the higher stalls are usually for lighter weight vehicles that can jump up to those peak power ranges quickly and easily. Typically trucks (at least heavier ones/ones that tow) have their peak power much lower in the curve and have correspondingly lower stalls to help get all that weight moving. Another potential issue is that the slipping with those higher rpm stalls causes a lot more heat which coupled with the hard use from a heavy truck and/or frequent towing can kill a trans pretty quickly without a top notch cooling setup. You should have a little leeway since your truck already has a 4l80e in it. That trans will take a lot of abuse but you'll still want to take care of it as you start modding other parts of your truck.